ON WEAK SOLUTIONS TO THE NONSTATIONARY VAN-ROOSBROECK SYSTEM WITH DISCONTINUOUS PERMITTIVITIES

In this paper we prove the existence of a weak solution to the non-sta tionary drift-diffusion equations (van Roosbroeck's system) of semicon ductor theory involving discontinuous permittivities. The proof is bas ed on an approximation of these equations by a system with bounded non -linearities, deriving a priori estimates on the approximate solutions and then carrying out the passage to limit. The discussion is complet ed by some regularity results for the weak solution under consideratio n. (C) 1997 by B. G. Teubner Stuttgart-John Wiley & Sons Ltd.